How to Pick a CDN

In talking with some of my CTO friends, one of the things that has come up is what a pain in the butt it is to choose a CDN. There isn’t any widely available testing tool and there are so many different things to think about when negotiating a contract with these people. While this list is hardly comprehensive, here are some things I wrote down to think about when we were evaluating CDNs.

What you know:
We want to spend as little as possible per GB.
We know we are going to be using more bandwidth month over month.
We don’t want to be locked into a contract that requires a high usage per month though, in the event we don’t hit those numbers.
We need to offer a reliable solution to our customers

Here are the elements of the contract to consider:

Contract Length
– Our usage is going to change as our business grows so we need to make sure our contract allows us to take advantage of that.
– We also do not want to be locked into a fixed amount of usage in the event we are not able to ramp up quickly enough.

Minimums
– For certain prices most CDNs have minimum usage requirements.
– Some will offer roll over (just like cell phone minutes) where you have a 12 month period to meet your minimums (which works nicely as your usage and bandwidth grows)
– Some allow ramp up times before you are required to meet your minimums (so you only pay for what you use for the first 90 days as an example)

Per Gig Pricing — Obvious the lower per GB the better. (check out cdnpricing.com for current pricing guidance)

Quality
– CDN quality is hard to quantify (there aren’t studies or things you can reference and all of them seem to have tip top keynote metrics).
– Once we have implemented a CDN we should run our own set of tests and determine their ability to deliver high quality content.
– We can look at examples of their other video customers, etc to get a feel for different levels of quality.
– Do they have different “quality” pricing? This is not an issue now, but could be at much higher usage levels.

Reliability
– Backup vendors: Do we need to offer a fall back CDN to customers? If so, is it worth employing a pay-for-what-you-use relationship with a CDN to fall back on if our primary CDN goes down?

Multiple vendor
– If we use two vendors then it is harder for us to achieve a bulk discount for higher volume.
– Using multiple vendors can allow us to get better results—comparing quality post implementation.
– More referrals from vendors for more customer leads.

SLAs
-Evaluate and negotiate on penalties and ramifications for SLA and service failures.

Termination
– Make sure we understand the conditions under what we can terminate the contract.

Feel free to leave comments if you think of anything I might have missed! 🙂

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Kate is known as one of the top technology leaders and CTOs. Her technical background is in creating and operating large-scale web applications. Her focus has primarily rested on SaaS applications and big data. She has extensive experience building and managing high-performance teams, and considers herself a fan of agile development practices and the lean startup movement. She is currently founding her own startup, popforms, but has held roles as developer, project manager, product manager, and people manager at great companies including Amazon and Microsoft. The last seven years she has been a VP of Engineering/CTO for companies like Moz, Decide (acquired by eBay), and Delve Networks (acquired by Limelight).
Kate is a keynote speaker, and she is also the curator of the Technology and Leadership Newsletter (TLN - www.techleadershipnews.com) and has a personal blog at katemats.com.